e6cf0ed92d wallet, rpc: listdescriptors does not need unlocked (Andrew Chow)
3280704886 Pass in DescriptorCache to ToNormalizedString (Andrew Chow)
7a26ff10c2 Change DescriptorImpl::ToStringHelper to use an enum (Andrew Chow)
75530c93a8 Remove priv option for ToNormalizedString (Andrew Chow)
74fede3b8b wallet: Upgrade existing descriptor caches (Andrew Chow)
432ba9e543 wallet: Store last hardened xpub cache (Andrew Chow)
d87b544b83 descriptors: Cache last hardened xpub (Andrew Chow)
cacc391098 Move DescriptorCache writing to WalletBatch (Andrew Chow)
0b4c8ef75c Refactor Cache merging and writing (Andrew Chow)
976b53b085 Revert "Cache parent xpub inside of BIP32PubkeyProvider" (Andrew Chow)
Pull request description:
Currently fetching a normalized descriptor requires the wallet to be unlocked as it needs the private keys to derive the last hardened xpub. This is not very user friendly as normalized descriptors shouldn't require and don't involve the private keys except for derivation. We solve this problem by caching the last hardened xpub (which has to be derived at some point when generating the address pool).
However the last hardened xpub was not already being cached. We only cached the immediate parent xpub and derived child keys. For example, with a descriptor derivation path of `/84'/0'/0'/0/*`, the parent xpub that is cached is `m/84'/0'/0'/0`, and the child keys of `m/84'/0'/0'/0/i` (note that child keys would not be cached in this case). This parent xpub is not suitable for the normalized descriptor form as we want the key at `m/84'/0'/0'`. So this PR adds another field to `DescriptorCache` to cache the last hardened xpub so that we can use them for normalized descriptors.
Since `DescriptorCache` is changing, existing descriptor wallets need to be upgraded to use this new cache. The upgrade will occur in the background either at loading time (if the wallet is not encrypted) or at unlocking time in the same manner that `UpgradeKeyMetadata` operates. It will use a new wallet flag `WALLET_FLAG_LAST_HARDENED_XPUB_CACHED` to indicate whether the descriptor wallet has the last hardened xpub cache.
Lastly `listdescriptors` will not require the wallet to be locked and `getaddressinfo`'s `parent_desc` will always be output (assuming the upgrade has occurred).
ACKs for top commit:
fjahr:
tACK e6cf0ed92d
S3RK:
reACK e6cf0ed
jonatack:
Semi ACK e6cf0ed92d reviewed, debug-built and ran unit tests and some of the descriptor functional tests at each commit. I'm not very familiar with this code and it could be clearer to the uninitiated IMHO, so I'm not confident enough to give a full ACK. Various minor suggestions follow, most of them for readability, feel free to pick and choose.
meshcollider:
Code review + functional test run ACK e6cf0ed92d
Tree-SHA512: ac27aade8644525cd65bfcaf27ff32afb974085b1451faf4ff68c6671a690bd6a41d4f39a33cbf461ae0fbe85995c0a4c08dbd36171da1c1d2a1d00053ad298d
722776c0fd